Kevin Reid: copied with reformatting from http://www.eros-os.org/pipermail/e-lang/2007-October/012279.html

2007-10-07T16:00:24Z

copied with reformatting from http://www.eros-os.org/pipermail/e-lang/2007-October/012279.html

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This is an overview of ways of debugging E programs.

==Causeway==

[[Causeway]] is a post-mortem debugger (operating on logs produced by the program) displaying which turns caused which other turns.

[http://www.erights.org/elang/tools/causeway/index.html]

==Host debugging==

E programs can be examined by the host platform ([[Java]], [[CL]], ...)'s debugging mechanisms. This is not especially pleasant in [[E-on-Java]] since the E code is interpreted, not compiled.

==Printing==

Good ol' "printf debugging". Your options here are to either pass around stderr so that you can get to it in the code; or you can send messages to the tracelog with this gimmick:

[[throw]] <- ("your trace here")

==Virtualization==

This is the intended full interactive debugging mechanism for E.

A [[vat]] is created whose implementation includes debugging support — most likely, it is implemented using objects living in a normal vat. The "host" vat can therefore run code which examines the "debug-vat" objects and execution state to examine/step/modify them.

The unique property of debugging access is that it allows the vat to be suspended and examined in the middle of a turn.

This hasn't been done yet because it requires what [[User:Kevin Reid]] [http://www.eros-os.org/pipermail/e-lang/2007-October/012279.html called] a "full VM" implementation of E: there must be no immediate callbacks from primitive code to E objects, as that would make interruption impossible.

[http://www.google.com/search?q=site:eros-os.org+e-lang+debug]

Debugging - Revision history

Kevin Reid: copied with reformatting from http://www.eros-os.org/pipermail/e-lang/2007-October/012279.html